MINNEAPOLIS — Nigel Cole is best known in the United States for the Helen Mirren comedy “Calendar Girls,” in which proper British ladies shock the establishment by posing au naturel for a charity calendar. There’s a parallel scene in his new crowd-pleaser, “Made in Dagenham,” with a battalion of upholstery seamstresses in a sweltering Ford factory slipping off their blouses before settling down to work.

“Oh yes. There’s a strict shirts-off clause in my contract,” the English director joked. In fact, the conditions in the Dagenham plant were decidedly uncomfortable. Not only did the 187 female workers have to peel off for comfort in summer, they opened umbrellas indoors to deflect incoming rain, and they made just a fraction of what their male counterparts on the assembly line earned. Their walkout for equal pay inspired Cole’s film. A hit in Britain, it is now opening in U.S. theaters.

Cole, promoting “Made in Dagenham,” is a graying sheepdog of a man with an infectious laugh. At 51, he’s too young to remember the 1968 strike and its part in Parliament’s 1970 passage of the Equal Pay Act, ending wage discrimination between men and women.

When he learned of the mostly forgotten showdown, he was intrigued, He interviewed some of the 30-odd surviving strikers to see if it would be appropriate — or even possible — to cast the labor-management confrontation as a comedy.

He calls the film “a victory parade.”

“Most films about working-class issues or social issues are kind of grim. Miserable,” Cole said. When the retirees told the filmmakers their cheerful, uplifting stories, however, “they made us laugh. There’s a British working-class humor that laughs in the face of adversity. It’s what got them through the war. Somebody falls over and breaks a leg and people have a good laugh about it. So we thought, maybe we can tell a story about a strike that’s positive and funny, too.”

Some of the film’s best jokes are firmly rooted in fact. The project was originally titled “We Want Sex,” reflecting the real- life moment when a strike banner reading “We Want Sexual Equality” failed to unfurl properly. Cole later decided that was inappropriate, but the film went out under its saucy original title in foreign markets. “The French film buyer said, ‘I bought a film called “We Want Sex,” and that’s what I’ll have!’”

Sally Hawkins, the chatterbox optimist of “Happy-Go-Lucky” plays the composite character of Rita O’Grady, a worker bee who finds her voice as a leader of the strike. After a factory shutdown, the men turn on their female co-workers. Rita’s husband complains that she’s neglecting her maternal responsibilities to lead the action, while the male-dominated autoworkers’ union views the ladies as an annoyance. Support for the woman’s strike comes from unexpected quarters.

“The film focuses on three very different women,” Cole said. The factory worker finds allies in a Ford boss’ ignored trophy wife (played by Bond girl Rosamund Pike) and a woman in a man’s world, the government’s labor minister, Barbara Castle (Miranda Richardson). “You couldn’t find three more different women, and yet they kind of connect. That was a really good idea by the writer that broadens the story, makes it a story about all women.”

The strikers themselves had concerns about how they would be portrayed, Cole said. “They were very worried that in a Hollywood way we would turn them into saints, or into people driven by a political agenda. They weren’t. They were ordinary women who had a beef. They had a complaint; they weren’t listened to because they were women, and they went on strike.”

Cole had a case of butterflies when he showed the film to the Dagenham strikers. “We were very nervous because we wanted them to love it. It was their story, they owned it, and you don’t want to release a movie where the people involved go to the press and say, ‘You know, it didn’t happen that way.’” Luckily, they gave the film their enthusiastic blessing.

“They all brought their children and grandchildren and after the lights went up they were saying, ‘We didn’t know about this, why didn’t you tell us about this great thing you did?’ Their lack of vanity, and the fact that they didn’t need to pursue glory or fame afterwards, I think, was very admirable.”